Kill It With…
by Right What Is Wrong
Summary: Regulus remembers something that can destroy Horcruxes. Oneshot.


Master Regulus trod closer to the basin. Kreacher watched, wide-eyed and trembling, as the young master dipped his goblet into the potion...

And flung it aside, the conjured cup disappearing in a puff of smoke the instant it hit the ground.

"No," Master Regulus said, his voice echoing around the vast cavern. "This is stupid."

"M-Master?" Kreacher asked, his heart beating faster; despite himself, he began to tremble at the thought of drinking the potion once more. A House-Elf must not want to defy orders, he mustn't, it was not allowed, he -

Master Regulus chuckled. When he turned back to Kreacher, there was a strange gleam in his eye.

"He thinks he's so clever," he said to no one in particular. "Too clever by half, I'd say." He looked across the water and chuckled again. "My, my, my," he said. "I'll bet this entire place is enchanted. Brilliant, really. I suppose that's what we all followed him for, isn't it? Ten times the wizard any of us will ever be."

"Master?" Kreacher ventured again.

"There's no need to waste a perfectly good locket, Kreacher," Master Regulus said, tossing Kreacher the locket he had procured. "If all goes well, perhaps you can give this to Cissy for her jewelry collection... She always was my favorite cousin..."

"But what is Kreacher to say to the family?" Kreacher asked. "Does this mean Master Regulus is not -"

"Oh, I'm not leaving here," Master Regulus said, crushing his dawning hopes. The young master looked all around, as though taking their dark surroundings in one last time. "It's just that I was overcomplicating matters." He took a deep breath. "It's only that - if the Dark Lord is not seen for a long time - then you can tell everyone." Distracted, he cast his gaze up to the ceiling, then lowered it to the ground and shook his head. "Tell Mother and Father - that I died a Dark wizard, always faithful to our ways. There's really nothing you can tell Bella - I'd stay clear of her, she won't be safe to be near. Cissy - same as my parents. And that I wish her a happy life." Master Regulus smiled wanly. "If you should ever see Meddy again - tell her one of us, at least, forgives her. She-"

"The blood-traitor?" Kreacher gasped without thinking, then hit himself for interrupting his master.

"No less a blood-traitor than the rest of us," Master Regulus said with unusual bitterness. "At least she's never, as far as I know, spilled pure blood. That's better than any of us can say now." He flicked a disgusted gaze toward his left arm. "At least someone's continuing our bloodlines rather than ending them."

Kreacher could only stare in stupefaction as Master Regulus continued. "And - if you ever see Sirius again -"

The young master's smile showed teeth. "Tell him I'm the better prankster."

In one smooth movement, Master Regulus turned and pointed his wand at the basin. "You'd best be gone the moment I say the word," the young master said over his shoulder. "As I said, everything here is enchanted. It will spread quicker than you can imagine. And I expect a fellow might show up who's offended at the sudden collapse of all his protections." He chuckled. "Oh, that will be funny. Pity I'll not be around to see that."

A sudden sheen of tears filled Kreacher's eyes. "Master Regulus-"

"Sorry, Kreacher," said the young master. "I just want you to know - it's been fun. And thank you."

Then he shouted an incantation so long and complex that Kreacher could not make the least sense of it, and all at once the basin was in flames.

But it was not just the basin: it roared up through the air, and down to the water, and all along the ground, burning brighter and hotter with every passing moment, and Kreacher stared in horrified fascination as it sped toward him and Master R-

"GO!"

And Kreacher could only obey.

As he vanished from the cave, tears pouring down his face, the last thing he heard was Master Regulus's mad, exhilarated laughter.

* * *

Did the infiltrator think Lord Voldemort was a fool? That he had not set alarms, that he could not feel them screaming before they were no more?

Whether this was Dumbledore's cunning or Regulus's folly, he would see to it that an example was made. He was not a child to be frightened by a burning dresser, he had grown cleverer and more guarded in hiding his precious things, none made a fool of Lord Voldemort -

When he Apparated to the mouth of the cave, he stared for an instant at the roiling mass of fire before him.

That instant was too long. The monstrous flames reared up, and were upon him.

He could not flee; he could not move; he could not even Apparate away. He opened his mouth to scream and the fire burned through his throat. His wand vaporized along with his hand. There was no thought; there was only agony.

In the last horrifying instants that his magic still preserved enough of his brain for awareness, he heard laughter.

* * *

 **Author's Note** : I am aware there is quite a distance between the basin and the mouth of the cave. For the purposes of this story, assume Fiendfyre spreads _quickly_ wherever there's magic for it to feed upon. As Regulus repeatedly emphasized, the entire cave is rigged with various enchantments... so it's pure fuel.

Really, if _Crabbe_ could learn Fiendfyre from one year of the Carrows, I'd think the scion of a family heavily involved in Dark Arts, who also happened to be _serving as a soldier in a civil war_ , would know it as well. And, while Dumbledore listed quite a few things to which the potion in the basin was immune, "being blasted with Fiendfyre" was not one of them.

Of course, we know from canon that wasn't the only Horcrux, so Voldemort's existence is (regrettably) not ended quite yet. Not that anyone, aside from a few Albanian hapless woodland animals, will know the difference for about a dozen years.


End file.
